Implementing a fuzzy menu for furnace

[yohannd1]

This is partially a suggestion and partially a showcase of this thing I've done.
I'm obsessed over fuzzy-picker menus like fzf, which consist in a list of text options, which can be selected through via keyboard.
Because of that, I've been thinking of adding something similar to furnace, which I believe could make the overall workflow easier, specially with the introduction of command palettes.

2023-05-24.17-16-40.mp4

Key points (mostly implemented):

• Fuzzy finding (currently very janky... it doesn't even work well in the video)
• Functional and easy-to-access with both keyboard and mouse
  • Use mouse OR arrow keys + enter to select
  • Quit using the ESC key

This still needs a lot of improvement:

• The UI looks hella wonky (keyboard-selected lines are prefixed with >)
• These pop-ups should stop everything else (I think "dialog" is the name for this, not sure)
• I still need to test it on Furnace (and apply it to something).

When I make this more decent, I want to try out porting the dialogs and other parts of the UI to this format:

• Save/Open file dialogs (this'll require a little bit of thinking as it's not a simple matter of "select from a list")
• New song dialog (this one is more simple, I'd say)
• Command palette (an overarching search menu with actions from the top menus and the context menu, akin to Atom/VSCode's command palettes, or the URL search bar in modern browsers)
• Settings menu (though a normal search bar probably does the job better here)

The biggest drawback I think this could have is actually making the UI harder to comprehend at first (specially the save/open file dialogs), but I don't think it'll be too much and the improvements brought by the command palette overshadow this in my opinion.